(Sebastian:) Why are these two pages separate?
unkx80: The distinction between the two pages is that how to read diagrams is focused on the diagrams themselves, while shorthand in describing diagrams is focused on the text that are used to describe the diagrams. In other words, given some diagrams and accompanying text in some foreign language the reader doesn't understand, the reader should be able to apply what is described in how to read diagrams but what is described in shorthand in describing diagrams is likely not be applicable.
Also, I personally do not like long pages, so I thought this is a good place to split them into two.